Modern vehicles are increasingly equipped with radio and communication devices which need suitable antenna structures for transmitting and receiving radio signals. If possible, the antenna structures should not protrude from the vehicle body, because they could interfere with the design of the vehicle shell. For this reason it is desirable to install antenna structures into the body in such a way that they do not protrude beyond the vehicle shell. This is known already for reception systems such as radio and TV reception systems which to some extent use multiple antennas to obtain a desired omnidirectional reception. Moreover, amplifiers are used in order to be able to keep the losses, caused by the maladjustment to typical antenna cables, low or even equalize them.
However, for cellular radio systems, for example, the use of an amplifier for impedance adjustment is generally too expensive; that is why the antenna structures were previously provided with suitable impedances which, however, for lack of space had to be installed in such a way that they protruded beyond the vehicle shell.
Therefore, it is an object of the exemplary embodiments and/or exemplary methods of the present invention to provide a multiband omnidirectional antenna for use in cellular radio systems whose impedance may be adjusted and which has a low installation height so that it may be placed within the vehicle shell.